Vehicle systems may include various vacuum consumption devices that utilize vacuum. These may include, for example, a brake booster and a purge canister. Vacuum used by these devices may be provided by a dedicated vacuum pump. In other embodiments, one or more aspirators (alternatively referred to as ejectors, venturi pumps, jet pumps, and eductors) may be coupled in the engine system that may harness engine airflow and use it to generate vacuum.
In one example embodiment shown by Bergbauer et al. in U.S. Pat. No. 8,261,716, a control bore is located in the wall of the intake such that when the throttle valve is at idle position, vacuum generated at the periphery of the throttle is used for a vacuum consumption device. Therein, the positioning of the throttle valve in an idle position provides a constriction at the throttle valve's periphery. The increasing flow of intake air through the constriction results in a Venturi effect generating a partial vacuum. The control bore is sited so as to utilize the partial vacuum for a vacuum consumption device.
However, as recognized by the inventors herein, in the approaches described above, the vacuum generation potential of the throttle may be limited. For example, a single control bore at one location in the intake, as shown in U.S. Pat. No. 8,261,716, is utilized by the vacuum consumption device even though vacuum may be generated at the entire periphery of the throttle. To use vacuum generated at the entire periphery of the throttle, more control bores may be needed in the intake passage. However, fabricating these control bores may result in significant modifications to the design of the intake passage which can increase related expenses. Furthermore, the throttle is unable to provide vacuum when in a closed position. This may limit a vehicle ability to replenish vacuum to the vacuum consumption device.
In one example, the issues described above may be addressed by a system comprising a venturi device displaceable along an axis of an intake passage, an inwardly projecting fixture radially spaced away from the axis and in sealing contact with an intake pipe of the intake passage, and a first venturi passage located between the venturi device and the intake pipe and a second venturi passage located between the axis and the fixture. In this way, the venturi passages annularly surround the venturi device and the fixture.
As one example, the venturi device comprises a plurality of perforations fluidly coupled to a throat of the first venturi passage such that vacuum generated in the passage may be supplied to an interior chamber of the venturi device. Likewise, the fixture comprises a plurality of apertures fluidly coupled to a throat of the second venturi passage such that vacuum generated in the passage may be supplied to an annular chamber of the fixture. The vacuum may promote air flow from the vacuum consumption device to both the venturi device and the fixture. Furthermore, displacing the venturi device along the axis may adjust an amount of vacuum generated in the passages thereby adjusting an amount of air flowing out of the vacuum consumption device to the venturi device and/or the fixture. As an example, displacing the venturi device toward the annular fixture increases an amount of vacuum generated.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.